Not to flagellate Behe, but…February 14, 2008 — Deacon Duncan
In response to my reference to Behe’s subtractive approach to science a commenter writes to ask for proof that science has a detailed, step-by-step proof that bacterial flagella evolved naturally.
In other words if there had already been detailed, specific accounts already published in the peer reviewed literature, Mr. Matzke would have felt no need to come up with a model himself. Which means that prior to 2003 the Neodarwinist facile, hand-waving assurances the that BF evolved were nothing but empty bluster.
If that was the state of the scientific knowledge of the origin of the BF in 2003, what has happened since then to justify your assertion that such natural processes have been discovered and the Behe is merely denying what we do know about such processes, and trying to discredit those who have discovered them. But where are the articles in the published literature? Why don’t you provide the cites? Or is it enough for you to simply assert, “It is so!?
What the commenter forgets, and what Behe would like us all to forget, is that it is not scientists who claim to have proven that the flagellum evolved naturally, but Behe who claimed to have proven that no such evolution is possible. The scientific issue, therefore, is not whether or not the flagellum evolved, but whether or not flagellar evolution can be conclusively ruled out.
Behe’s original mistake was that he originally tried to frame the flagellum argument as an actual, testable scientific hypothesis, based on the notion of irreducible complexity. In Behe’s words, “Without any one of a number of parts, the flagellum does not merely work less efficiently; it does not work at all. Like a mousetrap it is irreducibly complex and therefore cannot have arisen gradually.” The problem is that if you take away certain parts of the flagellum, you get a structure that, granted, does not function as a flagellum. This is not the same as being a structure that does not work at all, however. It functions as a Type-Three Secretory System, thus falsifying Behe’s claim that the flagellum as a structure is irreducible. Evolution does not require that the predecessors of a flagellum all function as flagella; it merely requires that they have some function which promotes the natural selection of that structure.
Behe’s response was to abandon the specific and objectively testable claim of irreducibility, and resort instead to the Beggar’s Argument: no matter how much you give him, he insists that more is necessary. It’s a subjective criterion, because there’s no objective specification of how much evidence is “enough”—it’s a moving target, a quantity that has no precise value beyond “more than whatever you happen to have.”
Behe’s insistence on ever-more specific detail is like a Holocaust denier insisting that unless you can document the names of each and every Jew that died in WWII, their specific cause, time, and place of death, and what they had for breakfast the morning before, you can’t prove that the Holocaust happened. The Beggar’s Argument is a form of denial. Anyone can look at the evidence available and then arbitrarily dismiss it as “not enough.” The true scientist, however, does not spend more time denying knowledge than acquiring it. Mere denial, on subjective and arbitrary grounds, is not science.
True science must be based on the principle that the truth is consistent with itself. If we grant this fundamental principle, we can look at the evidence together and easily see that the evidence is much more consistent with an evolutionary origin for the flagellum than it is with the ID non-explanation. For example, we know enough about evolutionary theory to know that it operates by non-directed interactions of organic molecules. This means that there is no directed or intentional goal that would drive it to move in a consistently “upward” direction: it might go upwards, it might wander, it might even backtrack at times. A so-called “irreducibly complex” structure needn’t arise by incremental additions to simpler structures, but would be more likely to arise by reduction of a more complex but non-irreducible structure that arose by incremental improvements coupled with a certain amount of “wandering” (i.e. co-opting of suitable structures for new and different functions).
This tells us what sort of evidence we ought to expect to encounter if evolution is true. For example, we ought to find structures that are similar in structure but different in function (like Type 3 Secretory Systems). And of course, that’s what we do find. More than that, we find abundant evidence that natural laws do exist and do cause things to interact in subtle and complex ways that produce results which seem far more sophisticated than we would naively expect nature alone to be able to produce.
We do not, by contrast, find evidence supporting the existence or influence of any Intelligent Designer, beyond the observations that are arbitrarily and superstitiously ascribed to Him. We know much about the nature of Nature, and how nature produces its results, and the cause-and-effect relationships that connect the things we see with the natural causes that produce them. Nothing like that is true about the so-called Intelligent Designer. And not only do we not know such things about this Designer, ID proponents actively oppose any attempts to find out!
While evolutionary theory is specific and detailed enough that we can analytically determine what sorts of evidence would and would not be consistent with it, ID is a complete non-starter, scientifically. Because we know nothing (and are forbidden to ask) about the motives, methods, and characteristics of the Designer, we have no way to determine what sorts of evidence ought to be produced by this alleged design process until after we look at what the evidence is. It’s strictly a matter of waiting for the arrow to hit before drawing the bulls-eye around it.
Even Behe, for all his personal incredulity, cannot say for sure that a truly Intelligent Designer might not be willing and able to design a natural system capable of evolving a flagellum, in ways that fallible mortals might find difficult to follow. No doubt if we are able, someday, to document a step-by-step process for evolving a flagellum, you can count on Behe to simply backtrack and claim that the Designer must have designed evolution.
Of course, theistic evolutionists have been doing that since the mid-1800’s. Scientifically, it’s a wise approach: though it assigns the credit to God in some ineffable sense, at least it has the dignity and integrity to focus on understanding the processes by which Creation actually works. And that’s the thing that gives science its value and authority. Behe’s subtractive approach to science is an insult to God’s intelligence, and a defiant refusal to acknowledge that God’s ways might actually be higher than his own.